In well procedures related to perforating, valves are sometimes combined with the perforating string moved downhole. The valves can be used to control flow in the downhole environment during, for example, production of fluids or isolation of wellbore regions for specific procedures.
The valves are actuated by a variety of mechanisms and procedures. In some designs, valve actuation is initiated by the shearing of shear pins. Other valves are explosively triggered or mechanically actuated by dropping a bar from a surface location. Each of these valve designs requires intervention for actuation.